Use of four isozymatic systems in lemon and lemon-like citrus cultivars to detect their genetic diversity

SummaryLeaf tissue samples of seven cultivars of Citrus limon, one of Citrus aurantifolia, one cultivar of Citrus latifolia, one cultivar of Citrus meyeri and two cultivars of local selections were analyzed for isozyme variation for malate dehydrogenase (MDH), glutamate oxaloacetate transaminase (GOT), tetrazolium oxidase (T.O.) and esterase (EST) to examine the biodiversity of farmers' selections and commercial cultivars. The GOT zymograms consisted of bands in two zones. The GOT isozymes are characterized by co-dominant expression. The enzyme differences were found to be adequate for distinction at the species level. MDH isozymes showed one or three bands. Two major areas of T.O. activity were identified. Zymograms for EST should prove useful as a diagnostic tool for cultivar identification in view of the extensive polymorphism of this enzyme.